﻿using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Media.Imaging;

namespace MCommons.MImage
{
    public static class ImageUtils
    {
        public static BitmapImage GetBitmapImage(string filePath)
        {
            var bitmap = new Bitmap(filePath);

            var tp = CreateImage(bitmap,80,100);

            return ConvertBitmap(tp);
        }

        public static BitmapImage ConvertBitmap(Bitmap bitmap)
        {
            MemoryStream ms = new MemoryStream();
            bitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
            BitmapImage image = new BitmapImage();
            image.BeginInit();
            ms.Seek(0, SeekOrigin.Begin);
            image.StreamSource = ms;
            image.EndInit();

            return image;
        }

        /// <summary>创建规定大小的图像    /// 源图像只能是JPG格式  
        /// </summary>  
        /// <param name="oPath">源图像绝对路径</param>  
        /// <param name="tPath">生成图像绝对路径</param>  
        /// <param name="width">生成图像的宽度</param>  
        /// <param name="height">生成图像的高度</param>  
        public static Bitmap CreateImage(string oPath,int width, int height)
        {
            Bitmap originalBmp = new Bitmap(oPath);

            if (originalBmp == null)
            {
                return null;
            }

            // 源图像在新图像中的位置  
            int left, top;

            if (originalBmp.Width <= width && originalBmp.Height <= height)
            {
                // 原图像的宽度和高度都小于生成的图片大小  
                left = (int)Math.Round((decimal)(width - originalBmp.Width) / 2);
                top = (int)Math.Round((decimal)(height - originalBmp.Height) / 2);


                // 最终生成的图像  
                Bitmap bmpOut = new Bitmap(width, height);
                using (Graphics graphics = Graphics.FromImage(bmpOut))
                {
                    // 设置高质量插值法  
                    graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                    // 清空画布并以白色背景色填充  
                    graphics.Clear(System.Drawing.Color.PaleTurquoise);
                    // 把源图画到新的画布上  
                    graphics.DrawImage(originalBmp, left, top, originalBmp.Width, originalBmp.Height);
                }
                
                return bmpOut;
            }

            // 新图片的宽度和高度，如400*200的图像，想要生成160*120的图且不变形，  
            // 那么生成的图像应该是160*80，然后再把160*80的图像画到160*120的画布上  
            int newWidth, newHeight;
            if (width * originalBmp.Height < height * originalBmp.Width)
            {
                newWidth = width;
                newHeight = (int)Math.Round((decimal)originalBmp.Height * width / originalBmp.Width);
                // 缩放成宽度跟预定义的宽度相同的，即left=0，计算top  
                left = 0;
                top = (int)Math.Round((decimal)(height - newHeight) / 2);
            }
            else
            {
                newWidth = (int)Math.Round((decimal)originalBmp.Width * height / originalBmp.Height);
                newHeight = height;
                // 缩放成高度跟预定义的高度相同的，即top=0，计算left  
                left = (int)Math.Round((decimal)(width - newWidth) / 2);
                top = 0;
            }

            // 生成按比例缩放的图，如：160*80的图  
            Bitmap bmpOut2 = new Bitmap(newWidth, newHeight);
            using (Graphics graphics = Graphics.FromImage(bmpOut2))
            {
                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                graphics.FillRectangle(Brushes.White, 0, 0, newWidth, newHeight);
                graphics.DrawImage(originalBmp, 0, 0, newWidth, newHeight);
            }

            // 再把该图画到预先定义的宽高的画布上，如160*120  
            Bitmap lastbmp = new Bitmap(width, height);
            using (Graphics graphics = Graphics.FromImage(lastbmp))
            {
                // 设置高质量插值法  
                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                // 清空画布并以白色背景色填充  
                graphics.Clear(System.Drawing.Color.White);
                // 把源图画到新的画布上  
                graphics.DrawImage(bmpOut2, left, top);
            }

            return lastbmp;
        }

        /// <summary>
        /// 创建指定大小图片
        /// </summary>
        /// <param name="img"></param>
        /// <param name="width"></param>
        /// <param name="height"></param>
        /// <returns></returns>
        public static Bitmap CreateImage(Image img,int width, int height)
        {
            Bitmap originalBmp = new Bitmap(img);

            if(originalBmp == null)
            {
                return null;
            }
            // 源图像在新图像中的位置  
            int left, top;

            if (originalBmp.Width <= width && originalBmp.Height <= height)
            {
                // 原图像的宽度和高度都小于生成的图片大小  
                left = (int)Math.Round((decimal)(width - originalBmp.Width) / 2);
                top = (int)Math.Round((decimal)(height - originalBmp.Height) / 2);


                // 最终生成的图像  
                Bitmap bmpOut = new Bitmap(width, height);
                using (Graphics graphics = Graphics.FromImage(bmpOut))
                {
                    // 设置高质量插值法  
                    graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                    // 清空画布并以白色背景色填充  
                    graphics.Clear(System.Drawing.Color.PaleTurquoise);
                    // 把源图画到新的画布上  
                    graphics.DrawImage(originalBmp, left, top, originalBmp.Width, originalBmp.Height);
                }
               
                return bmpOut;
            }

            // 新图片的宽度和高度，如400*200的图像，想要生成160*120的图且不变形，  
            // 那么生成的图像应该是160*80，然后再把160*80的图像画到160*120的画布上  
            int newWidth, newHeight;
            if (width * originalBmp.Height < height * originalBmp.Width)
            {
                newWidth = width;
                newHeight = (int)Math.Round((decimal)originalBmp.Height * width / originalBmp.Width);
                // 缩放成宽度跟预定义的宽度相同的，即left=0，计算top  
                left = 0;
                top = (int)Math.Round((decimal)(height - newHeight) / 2);
            }
            else
            {
                newWidth = (int)Math.Round((decimal)originalBmp.Width * height / originalBmp.Height);
                newHeight = height;
                // 缩放成高度跟预定义的高度相同的，即top=0，计算left  
                left = (int)Math.Round((decimal)(width - newWidth) / 2);
                top = 0;
            }


            // 生成按比例缩放的图，如：160*80的图  
            Bitmap bmpOut2 = new Bitmap(newWidth, newHeight);
            using (Graphics graphics = Graphics.FromImage(bmpOut2))
            {
                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                graphics.FillRectangle(Brushes.White, 0, 0, newWidth, newHeight);
                graphics.DrawImage(originalBmp, 0, 0, newWidth, newHeight);
            }
            // 再把该图画到预先定义的宽高的画布上，如160*120  
            Bitmap lastbmp = new Bitmap(width, height);
            using (Graphics graphics = Graphics.FromImage(lastbmp))
            {
                // 设置高质量插值法  
                graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
                // 清空画布并以白色背景色填充  
                graphics.Clear(System.Drawing.Color.White);
                // 把源图画到新的画布上  
                graphics.DrawImage(bmpOut2, left, top);
            }
            return lastbmp;
        }
    }
}
